Processing strip material



R. G. AREY Oct. 5, 1943.,

Filed Aug. 1. 1941 PROCESSING STRIP MATEIiiAL v 2 Sheets-Sheet 1 Oct. 5,1943. R. G. AIYQEY I 2,331,157

PROCES S ING STRIP MATERIAL Filed Aug. 1, 1941 '2 Sheets-Sheet 2 vi QRPatented Oct. 1943 UNITED STATES PATENT OFFICE PROCESSING s'mir MATERIALRalph G. Arey, Swampscott, Mass. Application August 1, 1941, Serial No.404,982

14 Claims. (01. 51-285),

The invention relates specifically to the manufacture of razor blades orlike cutting tools but involves principles applicable generally to thetreatment of. strip form material wherein the strip is caused to passthrough one or several operating stations where'work, such as grinding,polishing or the like, is done upon it. The objects are in general tosimplify and reduce the cost of production and to improve the quality,particularly the uniformity, of the product and blades or other articlesmade from it.

The drawings exhibit one of the ways in which these principles can becarried out and will suffice to illustrate them.

Fig. 1 is a side elevation, partly in section, of apparatusincorporating the invention.

Fig. 2 is a top plan thereof.

Fig. 3 is a cross view of a work station.

Fig. 4 is an enlarged detail thereof; and

Fig. 5 is a contracted side view of the loop of strip material.

In this exemplification the strip to be treated is a ribbon of steelwhich may be .007" thick and .125" wide, and when ground and sharpenedon both edges it can be cut or formed into sections, each constituting asafety razor blade.

A selected length of such strip or ribbon, marked I in the drawings, isfirst made into a closed loop, as by welding or otherwise joining itstwo ends. The dimensions of the strip are necessarily exaggerated in thedrawings. Such loop is placed on a trackway 2 on which it is caused tocirculate by means of a pair of rollers 3 and 4 which pull its upperstretch along the trackway in the direction of the arrow while the lowerstretch is allowed to hang free below the trackway or is otherwiseguided according to its length. The lower roller 3 is driven by avariablespeed motor 5 and the upper roller is leverweighted as indicatedto provide a non-slipping grip on the strip.

The form of the trackway is not of consequence and may be arrangedaccording to the nature of the work to be done, being in any eventprovided with appropriate means for guiding or retaining the strip torun in a fixed course, and with particular accuracy as it passes throughthe work station where is located the tool or tools which operate uponit. This guiding function is done in the present case by small rollers 6which are soft-surfaced so as not to dull a sharpedge in contact withthem.

At the work station the trackway is constituted of or includes a narrowrail or work table' l, slightly narrower than the ribbon itself anddesirably adjustable on the track structure 2, so as to support theribbon solidly against the pres sure of the members working on it. Inthe present case all the work performed by the machine is done at asingle station but it could be done at successive stations if desired.At the single -station indicated in the present apparatus both edges ofthe ribbon areground or sharpened and polished by a single abrasivebelt, the organization of which represents one of the independentfeatures of this invention. 4

This belt, 8, is cross-trained over two sheaves 9 and I0 symmetricallylocated on opposite sides of'th trackway or work table, one of thembeing under the pull of a spring I l to keep the belt taut. The twostretches of the belt are brought to bear on the ribbon on the Worktable at their point of crossing and, by virtue of their symmetricalarrangement, each bears upon the ribbon with the s'ame'pressure and at apreselected angle, one engaging the edge of the ribbon on one side ofits axis and the other engaging the other side as shown in Fig. 4. Thetwist incident to the crossing of the belt (360) is divided, part of it(180) being located at one side of the track, as indicated at 8a, inFig. 3 and the other part (180) on the other side of the track, asindicated at 827, both in the same stretch of the belt. -With thisdisposition of the twist, the single crossed belt requires to begrit-surfaced on only one of its faces which, besides the economy,affords the special advantage that both margins of the strip receiveidentical abrasive action, this being the necessary consequence of thefact that they are subject to the same surface at the same speed and atthe same pressure.

It is found that in the use of a single belt in this manner both sheavesshould be driven and for this purpose, in the present case, each has itsown'motor l2 and I3 and the two motors are synchronized to rotate at thesame surface speed. Also the, sheaves are mutually canted through .asmall angle so that the crossing stretches do not rub on each other.

For certain types of mechanical dry shavers a' razor blade with a convexedge rather than the customary concaveor hollow-ground edge, isdesirable, and it is apparent that the belt and work table arrangementabove described furnish a practical means for producing such an edge. Bycirculating the ribbon around the track through the work station'and atthe proper velocity the abrasive belt or such other tools as may be usedto do the work, can be driven at high speed and with a firm pressure onthe strip without risk of over-heating or drawing the temper of thelatter and without the need of any liquid coolant. It is only requiredthat the speed of the strip or ribbon be correlated to the rate of metalremoval so that any point on the ribbon passes out of the operatingstation before any critical temperature is reached. It then remainsmerely to cause the loop to make the appropriate number of circuitsaround the track for removing all of the metal required to be removed.In the return or lower-st te i t bb n loo the. i bon has ampleopportunity to cool off. With the high rate of grinding thus permittedthe thine.

nest stock can be ground and sharpened safely in a minimum of time andin apparatus which can be fully automatic.

While a high rate of grinding or metal removal is desirable in theinitial stages of producing a cutting edge it is necessary to'reduce therate and soften the action as final sharpness is approached. The laststage. of sharpening is merely one of polishing, the successive stages,be= ingooinmonly denominated as grinding, honing and stroppi e, By themethod of this inv n ion, as can be. performed in the apparatus abovedei- SQl'ibEd, this sequence. in the degree of metal re-. moval rate isproduced automatically. The abrasive belt such as 8', --wh w i s am andeiiective as a grinding agent, adapted to remove meta rapid y.- As.itvvea -s and its rit partieles become dislodged or pulverized, itbecomes moot r ike th bone, and towa h end of its. life when no more ris perceptible upon. t. itfu otions most, whol y as ap sh r str v her..It is. prac ical-to us abelt mad oi per in w ich case it is. he so pa ain that does. the oppins-v Now the en th o metal stripthet makes theloop. is l ct d: wit re e e to t ow thi k.- nes and. t e know a act rand e ul, liie of he ab i e be t (oi som an ard make so o brin a o he. rpoond t on he cut in ed ev ha e ome ready for th..t fi a r a me T us. in ial rc i s .roiie;h th vv r sta ion the r is ro n in ater oi to itsiti ho ed n in its final e r li s t re.- eeives th stropizi a ne ol r elser s ssi e y as ri der o e a ep or he one. s r p 2 t e n ire o era i noo s Wi ianeer o o erea in s i ed, o or verharpen n s a Whethe he e gee: ause p ol ged a t on o he orn down. e s l yv tonrod io tha f e -v Stll ano he and. i id nd t re o h invention o l ists n. the m an ne met doi producing an. accurately symmetrical cutting d e har ened a n th on nete s on th other- T is i ac om ish in ev impl manner by haliE-turningthe ends of the; steel sti e whee hey ereo in t first ste loe to. makethe loop. flhe half-turn is indicated In Fig. 5H and will e understoodto maintain a moreor less fixedposition at some point in the free run.By working on twisted loop it will be. observed that. first one side andthen the other side of the strip comes under the. action of the wetting.element. or elements. and, when a i-oele'. or rtie ne ebr s e e a h rdescr b d, he she le o o e es o eeeh ed o h ribboii. oeeds at. o xa tvea l reite iro eh lie shi les hon ng. en sw opi sta es. thusv producinafinlshe l bbon. heraene iih peri o bala ce oiilo t iedees hr ghoutheiull ens h f her lo ;e

itwillthiis be. parent tha he. moot-techi of the razor blades, or otherarticles, is a simple and largely automatic procedure, consisting merelyin making and installing the proper length of loop on the trackway andthe selected belt on the belt-sheaves, and then driving the three motorsat the appropriate speeds until the belt has ceased to have anybeneficial effect, a condition that can be observed by the appearance orfeel of the belt itself, at which time the s mmetri a sharpenin of both.edges will be ooinnl te. For st ibbon. o h dim given a loop length aboutl3" long driven at one circuit per minute is provided with razor edgesin about 15 minutes, the abrasive on the belt being size carborundum.For an extra fine ed e the beltis sometimes turned over at the end ofthe process, so that its plain paper side is against the work. and thenused for a few circuits. with a polishing compound applied to it.

When the belt is arranged as shown, the effect is, to.- produce an edgecqnvexin cross section and this'is desirable for theblades, fo Certa ntypes of dry shavers. The convexityis controlled by the adiustable positons. of the work; table. I or of the sheaves sand Ito): both. For othershapes of: edges incluzzlingv non-symmetrical Q 6 .Ghisel edges, thebelt. stretches can. be specially'guided in particular courses. accordint h hape desiredand for hqllgoweground' an. be substituted by abrasivewheels; as. will be understood, there being no limitation to th e na tiu ar-..matt. r.s. X ep s pecified th o aimshereoi:

When the work has been completed the. loop is removed from the trackvzayout into sections and its further iahripation into razor bladesor otherr icles d n in ny app opriate way- I claim:

1. The method. o pr ducing a. s ressed sur a n st ip materia h to unting. th ends of the st ip: to form. a oo time su loop through theaction of a tool hav rig a grito sin e hti sing t upon b th: s. o t its.pa sa es. hrou h an the me ho oroo ssins s r p mate el sta ion. e. l

Th methqdflz rea sing i i es r m st l? iei ompr ses; e s lv uni in theto'io rm a, w sted. o p, imll a W r a le and under re v WQIEK- ends e sile le ti g l it he ee ion oi ai ove rq riveo tool th ingon both s'desthereof; and there i is s eli oop; i itose t onscons itutii e the titles45. The methodoi ar nin oth oees of a metal s ri i io a omp ises. ormina o osetl loop of such strip, and circulating the loop throngs-[ he e iism e, crossrai ed. abr i belt at. h r ss oe, eo itottie str 't lereoiThe me hod, o produ ng es oft-strinm i ailw l i oou iorises reversals;-shiing the: ends, r he st ior n e loop. cir liettin su h: oss.- t roilghhe a tio' o-oi an; abras ice t o a ing. a r -surface on a sett r heels.-ns. nd con nui he. circ l i n uni-i1 the r t s ere. ev r and; he bae sintro s... th e e of thelstrip,

6. The method of producing. a stropped edge on; both. edge oi r p;material. which 'compris s r ever'sely uniting the ends, .of the strip;inform, a 9 1 ircula ng he loop hr ug he-simultar neous action ofcrossing abrasive belt-stretches, such belt-stretches having abrasivegrit on a softer backing, and continuing the circulation until the gritsurface on said stretches isWorn away and the softer backing thereofstrops the edges .of the strip.

7. The method of sharpening both edges of a metal strip which comprisesreversely uniting the ends of the strip to form a twisted loop andcirculating such loop through the action of a cross-trained abrasivebelt at the crossing point .of the stretches thereof, and adjusting thetwist of said stretches so that said stretches engage the work by thesame face.

8. The method of simultaneously sharpening both edges of thinrazor-blade strip which comprises pulling such strip in loop formthrough the action of crossing abrasive belt stretches, at the crossingpoint thereof, with one edge of the strip obliquely contacting one ofsuch stretches and the other edge similarly contacting the otherstretch, driving said stretches respectively in the direction of thetaper of the edge being sharpened by it, returning the strip through theaction of said stretches until the required amount of material has beenremoved and thereafter dividing the loop into individual sharpenedarticles.

9. The method of simultaneously sharpening both edges of thin metallicstrip which comprises cross-training a single abrasive belt on twosheaves occupying substantially the same plane, passing the strip to besharpened through the crotch formed by the crossing belt stretches andso that each edge of the strip obliquely contacts one of such stretchesand driving said belt so that each stretch thereby abrades the strip inthe direction of the taper of the edge to be sharpened thereby.

10. The method of sharpening both edges of thin metallic strip whichcomprises cross-training a single abrasive belt having an abrasivecoating on one only of its faces, on two supporting sheaves occupyingsubstantially the same plane, passing the strip to be sharpened into thecrotch formed by the crossing belts so that each edge of the stripobliquely contacts one of the stretches, adjusting said stretches sothat it is the abrasive face of the belt that has such contact in eachcase and driving the belt in the direction to cause each stretch tosharpen the strip in the direction of the taper of the edge to besharpened thereby.

11. Apparatus for sharpening both edges of thin razor blade stripcomprising a work table adapted for conducting and supporting the stripagainst the sharpening pressure, means for guiding the strip centrallyalong the table with its opposite edges overhanging the sides of thetable, driving means for causing the strip to travel along said table,and abrading means comprising crossing abrasive belt stretches, meansfor supporting said stretches so that their crossing point is locatedsubstantially centrally over said work table, and means for driving saidstretches to cause them to travel respectively from the crossing pointtoward and over the opposite edges of the strip on the table and each atan acute angle to the plane thereof.

12. Apparatus for sharpening both edges of thin razor blade stripcomprising a work table adapted for conducting and supporting the stripagainst the sharpening pressure, means for guiding the strip centrallyalong the table to expose its opposite edges for sharpening action,means for pulling the strip along said table, means for returning thestrip to the entrance end of the table for repeated travel thereover,and abrading means acting on the strip while on the table comprising asingle abrasive belt cross-trained over two sheaves respectively mountedon opposite sides of the table and each in a plane transverse to thetable and so that the crossing point of the belt stretches is locatedsubstantially centrally over said Work table, and means for driving saidstretches to cause them to move respectively from the crossing point indirections toward and over the opposite edges of the strip on the tableand at an acute angle to the plane thereof.

13. Apparatus as defined in claim 12 in which one-half of the twist inthe cross-trained belt occurs on each side of the table, so that thesame face of the belt acts on both edges of the strip.

14. Apparatus as defined in claim 12 in which the means for driving thebelt stretches comprises two driving agencies, one applied to each ofsaid two sheaves, operating them at exactly equal peripheral speed,whereby each belt stretch is subject to exactly equal tension as itengages the strip.

RALPH G. AREY.

